The development of Public Safety (PS) communication systems has resulted in a number of features for PS systems that are not seen in commercial operations. PS users often face situations that are entirely different from that of the user of typical communication systems. Police, firefighters, military users and other PS organizations face life-threatening situations in which reliable communications may be mission critical, and reliability consistent through severe environmental and operations stresses. Security is also a major concern, as it is desirable for PS systems to be able to operate free of intruders or, often, of unauthorized reception. Most PS systems currently in use are Push-To-Talk (PTT) systems employing any of a number of radio-based digital technologies.
PS organizations benefit from enhanced communication among specific groups, such as, for example, a particular sub-unit within a police department. Communication groups can be created to establish and maintain such groups, generally at the level of the PTT server. Typically, however, the procedures for setting up such groups are somewhat inflexible, so that communication groups tend to be static entities in practice. Security is one issue in the procedures for establishing and maintaining such groups, as group integrity may depend on ensuring that group sessions are available only to group members.
A number of situations arise in which it would be advantageous to include participants from outside the normal group, on a limited basis. For example, a police investigation could benefit from including a medical support person in specific communications about the investigation. Technological advances have enabled this sort of inclusion, as the PS communication server can interface with broadband or common solutions such as Open Mobile Alliance PTT over Cellular (OMA PoC), or similar, widely-used systems.
However, inclusion of participants from outside the normal group (hereinafter referred to as guest users) also presents an increased challenge related to security concerns. While a guest user may know the identity of the PS direct contact, the identities of other PS users may not be information desirable to pass to the guest user. Similarly, communications protocols, passwords, and other communication details are not information that should be shared outside the PS user community. Overcoming these concerns in a way that preserves communications security is a time-consuming process. By the time the security procedures can be completed, the desirability of communicating with the guest user may have disappeared.
To date, despite the desirability of including guest users on PS systems, security procedures have prevented the development of systems that can provide for that capability.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. Apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.